Job sorting the 2-wide output from a continuous web printer after cutting (or bursting) requires the sheets to be separated to eliminate the need for blank pages. The sheets in need of separation comprise an upper and lower sheet, overlapping and usually, but not always, coincident with one another. Usually, but not necessarily, the sheets are of identical dimensions. "Separation" of the sheets means to separate the overlapping sheets and arrange the separate sheets end to end, beside or adjacent one another, although separation can also mean disturbing the coincidence of the sheets and causing them to overlap instead.
Surprisingly, the prior art is void of an acknowledgment of the problem solved by the present invention, much less a solution. In U.S. Pat. No. 4,696,464 (Gammerler), for example, a method and apparatus is disclosed for uniting at least two streams of shingled laid out products (particularly folded products), almost exactly the opposite of the present invention.
Similarly, U.S. Pat. No. 5,575,466 (Tranquilla) discloses a means of adjusting the gap size between sheets fed by a sheet feeder. But this invention is used to adjust the gap between sheets that have already been separated, as opposed to a device that separates overlapping, coincident sheets.
Thus, there is a need for a method and apparatus for separating overlapping, coincident sheets.